Sheet separating and feeding devices are well known in the art. Most devices are designed for separating and feeding sheets of a uniform thickness, as for example, devices that separate and feed computer cards, separators for supplying copy sheets in a photostatic copier, and devices that feed letters. There are times when it is necessary to feed sheets having non-uniform thickness, either the non-uniformity being within a single batch of sheets or the non-uniformity existing on a batch to batch basis, i.e., the sheets of a single batch having the same thickness but the thickness varies from batch to batch. This invention is concerned with the need to feed sheets whose thickness varies from batch to batch. Prior devices have attempted to solve the problem of varying sheet thickness from batch to batch by providing means for adjusting the distance between the separator roller and the bump feed roller. This is usually accomplished by spring loading the separator roller so that it will yield upon the feeding of sheets of different thicknesses. This practice has not been found totally acceptable because utilizing devices whose rollers separate as a result of sheet thickness has resulted in jams and multiple copies being conveyed on occasion.